This invention relates to a method and apparatus for textile treatment. This means of textile treatment involves both, the rapid and repeated interchange between liquid in a tank and liquid trapped in fabric or yarn interstices and the rapid removal of air from these interstices. Thus, the process results in the more uniform and complete penetration of processing liquid into all interstices and capillaries of the fabric and/or yarn. Some of the potential applications include, but are not limited to: desizing, scouring, and chemical impregnation. The force and frequency with which the processing liquid penetrates into the fabric interstices also frequently makes practical the use of the process for fabric bulking and softening.
There are a number of relatively noneffective technologies currently utilized in effecting increased liquid exchange between fabric interstices and the liquid in a tank or bath. One means of attempting this process is the use of submerged idler rolls which redirect the fabric in the bath in order to increase the fabric path length within the bath through which the fabric is processed. The movement of the fabric through the liquid results in some agitation of the processing liquid. This general agitation process still relies primarily on diffusion to remove materials from interstices and capillaries. The effectiveness of this well established concept is rather limited.
A second means of attempting to achieve increased liquid exchange is the use of a water jet prior to the fabric entering the bath with submerged idler rolls as described above or prior to entering a nip between baths. The forced penetration of liquid into interstices is only momentary and not complete or constant and can only be described as infrequent.
A third means of attempting to achieve increased liquid exchange is the use of submerged nip rolls within the tank with submerged idler rolls. Once again, the forced penetration of liquid into interstices is only momentary and not complete or constant and can only be described as infrequent.
A fourth means of attempting to achieve increased liquid exchange is the use of a submerged suction slot formed in a roller and used in conjunction with submerged idler rolls as described in the first means above. This suction slot attempts to draw liquid through the fabric as the fabric passes this roller. As before, the forced penetration of liquid into interstices is only momentary and not complete or constant and can only be described as infrequent.
A fifth means of attempting to achieve increased liquid exchange is the use of a single rotary perforated drum with suction applied to the inside of the drum. This drum is submerged within a tank. This is a mechanically complicated device which can inflict fabric damage and is typified by being beset with sealing difficulties. The effectiveness, however, is a slight increase over these first four means.
A sixth means of attempting to achieve increased liquid exchange is the use of series of idler rolls located both above and below the bath. When the fabric passes between a lower roll submerged in the bath and an upper roller extending above, some excess liquid is removed by means of ultrasonic sound waves, applied to the fabric above the surface of the liquid in the tank. Also, water spray may be applied to the fabric in the region of application of ultrasonic sound waves to achieve increased liquid exchange. Both these means achieve only a few additional cycles of liquid penetration into the fabric interstices per pass by means other than the naturally occurring, slow process of diffusion. Furthermore, the equipment is relatively costly. It is believed that ultrasonic pulsing generates a great deal of micro-turbulence and cavitation within the fabric interstices and at the solid-liquid interfaces but does not result in a significant increase in the exchange between the liquid in the fabric and the liquid in the bath.
U.S. Pat. No. 3,183,690, issued to Zimmerli, discloses a device that creates a great deal of turbulence by yieldable wall areas. This produces a "sinuous wave action" that presents a sharp contrast to a plane of liquid.
U.S. Pat. No. 3,064,459, issued to Messinger, discloses an oscillating screen that is utilized to transport fabric by friction possibly resulting in abrasion and chafing. In this case, the screen is used to force the fabric through liquid as opposed to contacting the fabric with a plane of liquid.
The present invention solves these problems in a manner not disclosed in the known prior art.